Tile Grouting Made Simple – Sanded or Unsanded

Grouting comes hand in hand with any tiling job whether it’s the kitchen, shower, or even balcony. Grouting is also necessary when laying rougher stone slabs such as for a driveway or courtyard. However, simple as it is, it’s not just a matter of throwing together a random mixture of grout and water and hoping for the best. Assuming the tiles are waterproof, the grout seals the joints, and as such, must be strong and durable.

Cracking and shrinking are both common defects that occur in poorly done grout jobs. This is where a basic understanding of cement-based “fillers” come in handy. As per the title of this article, there are two general types of grout – sanded and unsanded. Sand acts as an aggregate that adds to the body of the grout, essentially strengthening it. However, there are instances where sanded grout is not recommended.

When to use Unsanded Grout

Sanded grout won’t properly fill tile spacing under an 8th of an inch, or about 3 millimeters. The larger grains of sand will prevent the grout from sinking sufficiently into the gap between the tiles, resulting in a very thin and weak grout thatGrouted floor tiles will most likely begin cracking within days of curing. This will be especially apparent when grouting wall or ceiling tiles, as gravity will make it virtually impossible to successfully press sanded grout into the cracks.

When compared to unsanded grout, sanded grout also has considerably less adhesive qualities while wet, causing the grout to “crumble” off slick tile walls while attempting grouting. This can be extremely frustrating. Solution: Use unsanded grout. This type of grout will either be completely sandless, or the sand it does contain will be extremely fine.

When to use Sanded Grout

Sanded grout is for spacing any larger than an 8th of an inch. Sanded grout is stronger and prevents failure due to cracking and shrinking. This is why grout that is sanded is necessary for larger gaps – because not only does it need to be stronger due to being a wider area but it also is subject to greater shrinkage for the same reason.

How to Grout

Let’s start with the tools you’ll need to do the job:

  • A rubber float spreader. This is a rectangular, hand-held tool used to spread and press the grout into the joints.

Grouting with Rubber Float

  • A mixing bucket to mix the grout.
  • A large grout sponge. This is used to clean the residual grout from the faces of the tiles before it cures.
  • A second bucket with clean water to rinse the sponge.
  • Grout.
  • Water.
  • A sealing agent (depending on type, it may be mixed in with the wet grout, or it may be applied after it cures).

Now that we have the tools, we need to mix the grout up with some water. Dump an appropriate amount of grout into the bucket, making sure you have some left in case it turns out too runny, and add water slowly. Too much water is one of the most common causes of bad-quality grout. The paste should be made to the consistency of cold mayonnaise – thick enough to hold its own shape, but workable.

The surface of the tiles should be clean and it helps for the gaps in between the tiles to be slightly damp. Bone-dry joints will quickly absorb water from the grout causing premature curing. As a rule of thumb for all cement-based construction materials, the slower it cures the stronger it will turn out. You now take your rubber float and begin pressing appropriate amounts into the joints.

Press the grout into the seams firmly with the rubber float in a direction diagonal to the tiles, or toward the corners, so as to prevent unintentionally scooping out any grout. Work systematically and only mix up what you can grout within 20 or 30 minutes. If you followed the instructions above, and the consistency is right, the grout should effortlessly ooze fully into the tile joints as you sweep the rubber float across.

After you finish applying the first batch of grout, wait about 20 minutes (during which time you can clean the float and bucket), and proceed to clean off the tile faces. This is an extremely important step, especially if the tile surfaces are rough in any way. Take your grout sponge and after wetting it in the bucket of water, wring it out as best you can. It should only be damp, not drippy in any way, as this may remove grout.

Taking this sponge, gently clean the tile surfaces, taking care to not disturb the grouted joints. You will need to periodically rinse your sponge as you work Grout cleaning spongeyour way across. Now you can repeat the process from the beginning. Remember to work patiently and uniformly, especially with the cleaning part. Trying to scrub off cured grout is a nightmare, and an overly wet sponge can not only remove the grout, but can dilute it, which will weaken it.

Waiting the right amount of time before cleaning ensures that the grout in the joints is firm enough to not be removed at the slightest touch but yet not cured to the point where it would be too difficult to clean. Rough tile surfaces can be troublesome to clean, but patiently work at it, and certainly don’t wait until it has cured. And you might be tempted to use a wetter sponge, but don’t!

Also, it doesn’t have to be cleaned perfectly! After it has been cleaned to an acceptable level, continue to the next batch. As with any intricate project that requires patience and finesse, going over what seem to be imperfect spots will often ruin it further. The joints in particular should only be passed over once – and lightly – with the cleaning sponge.

Other Tips

  • Sanded grout may scratch polished tiles and stone, in which case, an epoxy grout would be the recommended choice.
  • You may want to mist over your grout once a day for the first week to prolong the curing process. As mentioned above, the slower it cures, the stronger it will be. This is certainly recommended for dry and hot climates. You may even want to place a damp or wet sheet over the tiles to further delay the curing process.

Comments are closed.